Persons with mobility impairments often depend on a wheelchair or walking aid to facilitate mobility. As a result, they are frequently subjected to physical barriers and obstacles such as stairs and curbs. Current ADA legislation requires that these physical barriers be removed, and as a result, ramps have been designed to address this need. However, ramps can be very long and difficult to climb. Further, depending on the elevation change and available space, ramps may be impractical. One solution is a wheelchair lift. Wheelchair lifts for commercial buildings and private residences must be designed and tested to meet the requirements of the ASME Code: A18.1, SAFETY STANDARD FOR PLATFORM LIFTS AND STAIRWAY CHAIRLIFTS.
Platform lifts for wheelchairs have been developed for use in courtrooms, church pulpits, meeting chamber podiums, and other similar environments. These types of installations must not only provide a means for safe level changes, but must also be sensitive to decorum and surrounding architecture. Moreover, certain multi-level environments, such as courtrooms, require a lift that services multiple levels, such as the witness stand and the judge's bench. In a courtroom, the witness stand, or intermediate level, is not normally large enough to accommodate a hinged door. Thus the potential for an unsafe condition occurs when the lift platform is raised above the witness level, and conversely when the lift platform is lowered from witness level to courtroom floor level. This condition may also be present for a variety of other wheelchair lift assemblies when the lift is being moved.